File:Human NE cells exhibit species-specific differences in cell shape.jpg

English: "(A) Representative immunofluorescence images through whole mount organoids showing the morphology of neural progenitor cells (SOX2+), polarized around apical (ZO1+) lumens, revealed by sparse labeling with viral GFP in human (H9, IMR-90), gorilla (G1, G2), and chimpanzee (Chmp) organoids. Day 3 cells (top panels) are columnar and exhibit typical NE morphology. Day 5 (bottom panels) human cells still appear columnar, whereas gorilla and chimpanzee cells show a thinning of apical processes (arrows). DAPI is in blue. Red background signal outside the organoid comes from nonspecific uneven staining of surrounding Matrigel. Scale bar, 20 μm.

(B) Immunofluorescent staining for ZO1 on the surface of apical lumens showing the apical surface areas of individual progenitor cells at day 5 in human (H9, IMR-90), gorilla (G1, G2), and chimpanzee (Chmp) organoids. Perimeters of some individual progenitor cells are delineated in white. Scale bar, 10 μm. (C) Quantification of the apical surface area of individual neural progenitor cells of day 5 organoids show significantly smaller apical surface sizes of gorilla (G1, G2) and chimpanzee (Chmp) progenitor cells compared to human (H9, IMR-90). Measurements were performed on delineated ZO1 cell perimeters as shown in (B). Mean apical surface area/cell: H9 = 9.39 μm2, IMR-90 = 8.53 μm2, G1 = 4.48 μm2, G2 = 4.54 μm2, and Chmp = 3.55 μm2. ∗∗∗∗p < 0.0001, Kruskal-Wallis and post hoc Dunn’s multiple comparisons test, n (H9) = 341 cells from 8 organoids from 2 independent batches, n (IMR-90) = 121 cells from 4 organoids of 1 batch, n (G1) = 321 cells from 9 organoids from 2 independent batches, n (G2) = 172 cells from 5 organoids of 1 batch, and n (Chmp) = 277 cells from 6 organoids and 2 independent batches. Boxplots show median with whiskers representing min-max values; data points on the boxplots represent individual cells. (D) Representative immunofluorescence images through whole mount human (H9) and gorilla (G1) organoids with superimposed individual segmented cells (white) showing the 3D morphology of individual GFP+ progenitors. Note the thinning of apical processes observed in gorilla at day 5 that becomes pronounced in both species by day 10. Scale bar, 10 μm.

(E) Quantification of the volume normalized to surface area of the apical processes of human (H9) and gorilla (G1) neural progenitor cells on day 3 (left), day 5 (middle), and day 10 (right), showing significantly reduced apical volumes in gorilla cells relative to human at day 5. The apical processes of segmented cells directly below the cell body were used for quantification. Mean apical process volume:surface area ratio: human day 3 = 1.21, gorilla day 3 = 1.31, human day 5 = 1.23, gorilla day 5 = 0.76, human day 10 = 0.66, and gorilla day 10 = 0.65. Mann-Whitney U, ∗∗∗∗p < 0.0001, two-tailed, n (day 3 human) = 10 cells, n (day 3 gorilla) = 8 cells, n (day 5 human) = 14 cells, n (day 5 gorilla) = 16 cells, n (day 10 human) = 8 cells, and n (day 10 gorilla) = 8 cells. Error bars are SD."